Skin clamp



' clamps have a projection into the body member further bushing remains and fills the Patented May 6, 1941 UNITED STATI-:s PATENT OFFICE- SKIN CLAMP Donald H. Finkle, Los Angeles, Calif.

ClaimS.

My invention holding two sheets of metal and especially to a clamp for eoncentrically aligning holes in the two sheets.

In the construction of an airplane fabricated from metal parts or one that has metal skin yor covering to the wings or is placed over structural members and then holes are drilled through the bers land therivets placed through the holes. Through the skin vof one wing or'fuselage, several hundredand sometimes thousands of these rivet holes are necessaryand when iilled they must all align to permit the rivets to be placed.

'I'here have been several skin clamps invented prior to my' invention, the best of which is the one shown in the patent to 2,159,655. The De Mooy clamp and all other which is substantially the diameter of the holes-to be aligned but one side of this projection has been cut away so as to provide a slot for the operation of the clamping member y As some of these skinclamps are hole with a diameter of I inch, the cutting away of a portion of this projection seriously weakens the projection and causes excessive wear and breakage. In the 'place of the projection used in prior clamps, I use a bushing that is 'composed of a circular tube of substantially the which it is to be inserted. This tubular shape reinforces itself; and lprevents excessive wear and breakage,

A clamp const cted in accordance with-my;

` invention has a body member through which is insertedv a wire having a hook on the end thereof and actuated by a spring. When the body member is pressed down on the spring, the hook member can be placed through the rivet holes and upon the release of the spring the hook 4on the wire and the adjacent body member will clamp the body member and skin tightly together. To provide means for concentric augment of the holes', a bushing of the same diameter as the hole into which the particular clamp is to be placed is slidabiy mounted in the body member' surrounding the wire comprising the hook member. This bushing is spring' actuatedand, when the clamp is 4compressedfor insertion in a hole, the bushing is extended out through the body member and at the same time the wire hook member is forced outwardly from the end ofA this bushing. When the compression on the clamp is released', the bushing cannot than the hook 'member 'and the holes and maintains them in concentric alignment. y

It is an object of my invention, therefore, to

relates to a clamp -for use in fuselage, the metal skin De Mooy No.

draw back r appucaun october z, 1940, seria No. ssasss skin and structural mem- `produce a clamp for use engaging a slot 8 in the cap sion between the end i and a in the fastening of the skin to the body member of an airplane.

Another object of my invention is to produce -a clamp which isl capable of passing through a rivet hole and maintaining the said rivet hole in concentric alignment'and at the same time firmly holding the two parts to be riveted together.

Another object of my invention is to produce a skin clamp which will not be. subject to excessive wear and breakage.

Other objects and advantages of my invention will be apparent from the accompanying description of the preferred embodiment of my invention.

Fig. 1 is a longitudinal section.

Fig. 2 is an elevation of the opposite end from the clamping end.

Fig. 3 is a longitudinal section of a modification.

Fig. 4 is an elevation partially in section showing a' skin clamp in working position.

Fig. 5 is a view partially in section of the clamping end'.

A clamp constructed in accordance withV my invention has a body member I, having a hole 2 for `the reception of the bushing 3. A wire rod l is inserted through a cap 5 and the bushing 3 and an end 6 bent at right angles. wire rod has an end 1 bent at 'right 5. To maintain tenface 9 of the body and thus clamp materials between if is provided-'which presses I0 of the capi and the 4inner end l2 of the bore il.

To maintain the clamp in the holes in two pieces of material and align those holes concentrically, the bus 3, of,J substantially the diameter of the holes, is made slidable in the hole 2 and when elected therefrom by the action of a spring Il substantially lls the holes in the material. The spring Il engages end ISof the bushing 3 and end I6 oi? cap 5.' To clamp and aligndiiferent sized holes in the material to be clamped, a clamp with a bushing 3 substantially the diameter of the 'hole must be used.

Ihave found that the only relation between the spring il and the spring I I isk that the spring I4 must be shorter land of less power than the slight change in power spring Il. However, any

` isvsuilicient to make vent contact with the tool The body member I has rib I1 completelyen# circling it to provide a grip for a compressing The angles and `|9 in metal plates 20 bushing is plac tool. Any tool similar t can engage a face I8 of may be used for compre In the operation of tool operating on the ri the springs II and I4 o a pair of pliers which the cap 5 and the rib I 7 ssing my clamp.

my clamp. a compression" b I'I and cap I compresses forcing out the wire rod 4 and bushing 3 as shown in Fig. 5, thus permitting the insertion of the end 6 through holes and 2| and then placing holes I9. As the bushing ereon, it cannot be come body member I and the l nded outwardly therefrom of the bushing 3 in the 3 has a shoulder 22 th pletely ejected from th wire rod 4 may be exte as shown in Fig. 5.

The end B of the wir er length than the diameter of the holes it would be impossible to insert it therethr unless the material was very thin.

Because of the close t between the inside bore of the bushing 3 and the Wire rod 4 ed in the holesl I9 and the compressiontool released, the end 6 yond the edges of the holes I9 a the metal -plates 20 and 2| be the face 9 of the`body membe Fig. 4

e rod 4 cannot be o1' greatough nd rmly clamp tween itself and r I as shown in semble.

I have found a definite proportion in the lengths o1' the springs 2l and 24 are necessary to my clamp. For example. a two sheets of spring '24 will cause far from the body member the grip of the clamp, or not g I to emerge too I and thus weaken the tace l bears a relatio the bushing 3. In the e ness should be inch.

` Itwill be see Spring 2 nship to the action oi' xample given this thickbeyond the end of t the insertion of the It should be no 24 should be 0i' he bushing 3 so as to allow end l through the rivet hole. ted that both springs 2l and exactly the same diameter of bushing "l ened so that at all times it extends 9s` inch be- 7 said holes to maintainv when the will extend be- Ayens the race n, thus givin g the bushing an effective length of 1. inch.

In this modication (Fig. 3) the end 6 of the wire rod 4 is not bent at a right angle as in Fig. 1. At substantially the'angle shown in Fig. 3, the grip on -the metal plates is increased by the which forces the rod tight against the opposite side of the bushing 3 from which the end 6 is bent.

While I have described the preferred embodiments of my invention, I am not limited to any of the specific forms therein set forth except as described in the appended claims.

I claim:

1. In a clamp for concentri of -the same diameter in\tv vo or more sheets of metal, a body member, a. bushing slidable in said member of substantially the diameter of said holes in concentric cally aligning holes centrically aligning holes in two or more sheets of a bushing slidable in said tantially the diametervoi' member when in' cla .3. In a clamp for mping position concentrically aligning holes body member, on said bushing to permit said wire rod to be extended beyond the end of said bushing, said being oi' substantially the diameter of ntric alignsaldhole's to maintain them in conce mentl 5. a clamp for concentrically aligning holes oi' the same diameter in DONALD H. FINKLE.

said holes in concentric 

